S. FUKUDA, S.ANAMI , C. KUBOTA, M. KAWAMURA, S. YAMAGUCHI, M. ONO, H. NAKANISHI (KEK), S. MIYAKE*, M. SAKAMOTO*, (Toshiba)
The construction of the 60-MeV linac has been started as the low-energy front of the KEK/JEARI Joint Project for high-intensity proton accelerator facility in KEK. The linac comprises a volume-production type negative hydrogen ion source, 3-MeV RFQ linac, 50-MeV Drift-tube linac (DTL) and a separated DTL. The accelerating frequency is 324 MHz. Five UHF klystrons are used as an rf source and their ratings have a maximum power of 3MW, a pulse width of 700 microsec (flat top is 650 microsec)and repetition rate of 50 pps. We have manufactured a prototype klystron and tested. In this paper, the specification and developments of the rf source including WR-2300 WG system are summarized. We have tested up to the output power of 2.5 MW but during the test process the strong oscillations due to the back-going electrons from the collector were observed. These phenomena were analyzed experimentally and theoretically to solve them. This is also described in this paper and related papers.
 Y. Yamazaki and the JAERI/KEK Joint Accelerator Team, 'The Construction of the Low-Energy Front 60-MeV Linac for the JAERI/KEK Joint Project', in this conference.
 JHF Project Office, 'JHF Accelerator Design Study Report', KEK Report 97-16 (1999).
 Z. Fang, S. Fukuda, S. Yamaguchi and S. Anami, 'Simulation of back-going electron from a collector of klystron', in this conference.
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